The famous biologist and philosopher E.O. Wilson coined the word biophilia to describe the instinctive human bond between humans and other living systems. One way human biophilia is expressed this time of year is in the placement of evergreen boughs, wreaths, and trees in homes and public spaces. Before the invention of plastic foliage and even before the first Christmas, evergreens were celebrated as symbols of eternal life and incorporated in celebrations across North Africa, Europe, and Northern Asia. And before the word 'evergreen' was first used to refer to plants that keep their leaves year-round, English speakers referred to them as 'wintergreen'. Today the meaning of the word 'wintergreen' has narrowed and refers exclusively to broadleaved plants in the genus Gaultheria.